Summary
The fine-structure of four genes, A-P, A-P1, A-P2 and A-P3 in the flax rust organism, Melampsora lini, that control pathogenicity on the host, Linum usitatissimum, has been investigated by using a mass-screening procedure to search for rare recombinant progeny. Three presumptive recombinant individuals were recovered from amongst 3160 dikaryotic test-cross progeny and seven from a second test in which haploid basidiospores were screened for recombinants. From the pathogenicity phenotypes of the presumptive recombinants, and their frequency of occurrence, it is concluded that genes A-P, A-P1, A-P2 and A-P3 are sufficiently closely linked to belong to the same cistron. However, the possibility that they belong to separate, closely-linked cistrons can not be excluded: if they do belong to separate cistrons, then the data suggest that these are contiguous. A tentative gene order A-P A-P2 A-P1 A-P3 is proposed.
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Dinoor, A, Khair, J, and Fleischmann, G. 1968. Pathogenic variability and the unit representing a single fertilization in Puccinia coronata var. avenae. Canad J Bot, 46, 501–508.
Flor, H H. 1955. Host-parasite interaction in flax rust—its genetics and other implications. Phytopath, 45, 680–685.
Flor, H H. 1956. The complementary genic systems in flax and flax rust. Adv Genet, 8, 29–54.
Flor, H H. 1958. Mutation to wider virulence in Melampsora lini. Phytopath, 48, 297–301.
Flor, H H. 1959a. Differential host range of the monokaryon and dikaryons of a euautoecious rust. Phytopath, 49, 794–795.
Flor, H H. 1959b. Genetic controls of host-parasite interactions in rust diseases. In Plant Pathology—Problems and Progress 1908–1958, ed. C. S. Holton, pp. 137–144. University of Wisconsin Press.
Flor, H H. 1964. Genetics of somatic variation for pathogenicity in Melampsora lini. Phytopath, 54, 823–826.
Flor, H H. 1965a. Inheritance of smooth-spore-wall and pathogenicity in Melampsora lini. Phytopath, 55, 724–727.
Flor, H H. 1965b. Tests for allelism of rust-resistance genes in flax. Crop Sci, 5, 415–418.
Lawrence, G J. 1977. Genetics of pathogenicity in flax rust. Ph.D. thesis, University of Adelaide.
Lawrence, G J. 1980. Multiple mating-type specificities in the flax rust Melampsora lini. Science, 209, 501–503.
Lawrence, G J, Mayo, G M E, and Shepherd, K W. 1981. Interactions between genes controlling pathogenicity in the flax rust fungus. Phytopath, 71, 12–19.
Mayo, G M E, and Shepherd, K W. 1980. Studies of genes controlling specific host-parasite interactions in flax and its rust. 1. Fine structure analysis of the M group in the host. Heredity, 44, 211–227.
Paszewski, A, Prazmo, W, and Jaszczuk, E. 1971. Multiple recombinational events within the 84w locus of Ascobolus immersus. Genet Res, Camb, 18, 199–214.
Person, C. 1959. Gene-for-gene relationships in host-parasite systems. Can J Bot, 37, 1101–1130.
Shepherd, K W. 1963. Genetics of host-pathogen interactions. Ph.D. thesis, University of Adelaide.
Shepherd, K W, and Mayo, G M E. 1972. Genes conferring specific plant disease resistance. Science, 175, 375–380.
Statler, G D, and Gold, R E. 1980. Comparative virulence of basidiospore and urediospore cultures of three pathogenic races of Melampsora lini. Phytopath, 70, 555–557.
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Lawrence, G., Shepherd, K. & Mayo, G. Fine structure of genes controlling pathogenicity in flax rust, Melampsora lini. Heredity 46, 297–313 (1981). https://doi.org/10.1038/hdy.1981.42
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DOI: https://doi.org/10.1038/hdy.1981.42